Furnace



3 Sheets-Sheet 3 ELECTRIG FURNACE Filed March 6. 1926 F. YT. COPE ET AL e nU Nov. 1927.

oL l O Patents-d Nov. 1, 1927.

UNITED STATES PATENT OFFICE."

FRANK T. COPE AND BOLAND F. BEHZINGR, OF SALEM; OHIO, ASSIGNORS TO THE ELECTRIC F'UENACE COMPANY, OF SALEJL OHIO, A CORPGRATION OF OI-IIO.

ELECTBIC FURNACE.

Application filed March 6,

The invention relates to electric `furnaces of the metallic resistor type and more particularly to means tor supporting sinuous re sistor grids, particularly beneath the hearth of the furnace.

In the type of furnace to which the 1nvention is especially adaptable the working hearth of the furnace is'made up of'plates of heat resisting alloy supported above the base of the 'furnace upon refractory pers, the metallic resistors or grids being located beneath said hearth plates. A

It is usual practice for these resistor grids to rest directly upon the floor or base of the furnace but owing to the fact that spaces mustbe left between the adjacent edges of the hearth plates, in order to provide for erpansion under high temperature, a considerable amount'ot scale, from the articles being heated or heat treated upon said hearth plates, drops through these spaces upon the floor or base of the 'urnace frequently short cirouiting the metallic resistor.

The object of the present improvement is to provide means for supporting these metallic resistors or grids at a point spaced above the floor or base of the turnace whereby scale dropping through the spaces between the hearth plates will slide or ;tall ofi` of the sinuousresistor upon the floor or base of the urnace, preventing danger of short circuitng of the resistor; means being provided for easily removing this accumulation of scale 'from the floor before it has become pled high enough to contact with theresistor, e p

The above and other obj-ects may be attained by providing main piers `for supporting the edge portions of the hearth plates and secondary piers for supporting intermediate portions of the hearth plates, the sinuous resistor extending substantially from one main pier to the next adjacent main pier certain portions of the intermediate piers being cut out to support alternate loops of the resistor while the intermediate loops thereof are supported upon rods or pins extended between adjacent piers.

An embodiment of the invention is illustratod in the accompanying drawings, in which Figure 1 is a vertical longitudnal section through a furnace embodying the invention;

Fig. 2, a transverse sectional View of the same;

1926.' Serial No. 92,695.

Fig. 3, a fragmentary plan sectional view showing portions OI" the resistor and hearth plates removed for the purpose of illustration;

F i g. 1, an'enlarged plan sectionalview of a portion or". the resistor and-one of the supporting rods;

Fig. 5, a detached perspective view of the supportingrod, and` p Fig. 6, a detail sectional view through the cut out portion of one of the piers showing the beveled upper edge thereot; Similar numerals refer to similar parts throughout the drawings.

' The furnace may coniprise the base 1, side walls 2 and root 3, formed of suitable refractory material and enclosed as by the metal casing 4-. The usual structural members 5 may be provided for supporting-the brick work, which may be reinforced by the vertical structural members 6 which carry the roof supporting structure 7.

The working hearth of the furnace is composed of plates 8 of heat resisting metal, supported upon piers extended upward :from the base or floor 1. V

These piers are preferably formed of( refractory material and maycomprise the longitudinal main piers 10, having heat ressting alloy Caps 11 supporting the edge portions of the hearth plates and the secondary piers 12 which are located between the main piers to reduce the-plate span between the same, for the purpose of overcoming distortion or' sagging of the hearth plates when heavily loaded under high temperatures. p i

'With this constructionof main and secondary piers a space is left between the pers in which the resistors may be mounted. In carrying out the present invention each of the secondary piers 12 has its upper portion cut out at spaced intervals as shown at 13, to a point midway betweenthe hearth plates and the brick floor 1. The resistors, indicated generally at 14 are ot' sinuous shape and may comprise alternate wide and narrow loop portions 15 and 16 respectively. These wide loops 15 are supported in the cut out portions 13 of the secondary piers, the narrow loops 16 being located in the spaces between the piers. i

The upper halt of each cut out portion 13 is beveled as shown at 15 in order to provide no shoulder to retain scale which drops from the articles being heated, through the hearth, these beveled edges upon the resistor supports causing the scale to drop upon the floor, thus assuring no possibility of short circuiting of any portions of the resistors by accumulation ot' scale thereon.

For the purpose of supporting these narrow loops, rods 17, of suitable heat resisting metal, are located transversely between the piers and provided with spaced upright prongs 18 between which is received the end portion oi" each loop 16.

The resistor is thus supported midway between the floor and hearth plates and since the same is of substantially triangular cross sectional shape any scale which drops' thereon will easily slide or drop ofl and be deposited upon the floor beneath the resistor, preventing danger of short circuiting.

In order to keep the floor of the urnace clean a small opening 19 may be provided at each end wall of the furnace for the purp-ose of entering an air hose or cleaning tool for removing the accumulation of scale froni time to time.

We claim:

1. An electric turnace including a floor, piers eXtended upward froni the floor, a hearth comprising a plurality of plates mounted upon said piers, and a resistor grid supported between the piers and intermediate the hearth and floor.

2. An electric furnace including a floor, piers extended upward from the floor, a hearth mounted upon said piers, and a resistor grid supported between the piers and intermediate the hearth and floor.

3. An electric 'urnace including a floor, piers extended upward from the floor, a hearth mounted upon said piers, certain o' said piers having cut out portions, and a sinuous resistor grid having loops supported in said cut out portions and being spaced intermediate the hearth and floor.

4. An electric furnace including a floor, piers extended upward from the floor, a hearth comprising a plurality of platcs,

mounted upon said piers, certain of said piers having cut out portions, and a sinuous resistor grid having loops supported in said cut out portions and being spaced between the hearth and floor. e

5. An electric turnace including a floor, piers eXtended upward from the floor, a

hearth mounted upon said piers, supporting rods located between the piers intermediate the hearth and floor, and a resistor supported upon said rods.

6. An electric furnace including a floor, piers extended upward from the floor, a hearth comprising a plurality of plates mounted upon said piers, supporting rods located between the piers intermediate the hearth and floor, and a resistor supported upon said rods.

, 7. An electric furnace including a floor, piers cxtended upward froni the floor, a hearth mounted upon said piers, certain of the piers having cut out portions, supporting rods located between the piers, and a sinuous resistor grid having certain loops supported in said cut-out portions and certain other loops supported upon said rods, and being spaced between the hearth and floor.

8. An electric furnace including a floor, piers eXtended Upward froni the floor, a hcarth coinprising a plurality of plates n'ounted upon said piers, certain of the piers having cut out portions, supporting rods located between the piers, and a sinuous resistor grid having certain loops supported in said cut outportions and certain other loops supported upon said rods, and being spaced between the hearth and floor.

9. An electric turnace including a floor, piers extended upward from the floor, a hearth mounted upon .said piers, certain of the piers having cut out portions, supporting rods located between the piers, and a sinuous resistor grid having certain loops supported upon said cut out portions and certain other loops supported at their ends only upon said rods.

10. An electric turnace including a floor, piers extended upward 'from the floor, a hearth nounted upon said piers, certain of the piers having cut out portions, support ing rods located between the piers, and a sinuous resistor grid having certain loops supportedupon said cut out portions and certain other loops supported at their ends only upon said rods, said rods having prongs between which the end o't the loop is receivcd.

In testinony that we claim the above, we have hercunto subscribed our names.

FRANK T. COPE. ROLAND F. BENZINGER.

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